Asteroids in the Distance
Explanation:
Rocks from space hit Earth every day.
The larger the rock, though, the less often Earth is struck.
Many kilograms of space dust pitter to Earth daily.
Larger bits appear initially as a bright meteor.
Baseball-sized rocks and ice-balls
streak through our atmosphere daily,
most evaporating quickly to nothing.
Significant threats
do exist for rocks near 100 meters in diameter, which
strike the Earth roughly every 1000 years.
An object this size could cause
significant tsunamis were it to strike an ocean,
potentially devastating even distant shores.
A collision with a massive asteroid,
over 1 km across, is more rare,
occurring typically millions of years apart, but
could have truly global consequences.
Many asteroids remain
undiscovered.
In the
featured image, one such asteroid -- shown by the long
blue streak -- was found by chance
in 1998 by the Hubble Space Telescope.
A
collision with a large asteroid
would not
affect Earth's orbit so much as
raise dust
that would affect Earth's climate.
One likely result is a global extinction of many species of life,
possibly dwarfing the ongoing
extinction occurring now.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
